基于典范对应分析的滨海湿地土壤季节性盐渍化特征

为了更好地开发利用黄河三角洲湿地土壤资源和生态环境建设,运用单因素方差分析(One-way ANOVA)和典范对应分析方法(CCA),对黄河口湿地0—10 cm土壤全盐量(TS)、盐分离子组成、pH、钠吸附比(SAR)、电导率(EC)的季节性变化特征及数量关系进行了分析。结果表明:该区土壤属于盐土类型,春季(5月)、夏季(8月)、秋季(10月)全盐含量均高于17.9 g/kg,且春季、秋季的含盐量高于夏季,造成春、秋季积盐,夏季脱盐。盐分阳离子以Na~+为主,阴离子以Cl~-为主,除Mg~(2+)在夏季、秋季和Cl~-在秋季表现出强烈的变异性外,其余离子在不同季节均表现出中等强度的变异性。春季,Cl~-与Na~+、Mg~(2+),SO■与K~+;夏季,Cl~-与HCO~-_3,SO■与Mg~(2+)、Ca~(2+),Ca~(2+)与Mg~(2+);秋季,Cl~-与SO■,SO■与Mg~(2+),Ca~(2+)与Mg~(2+),均有很好的关联性。pH值均介于7.7—8.1之间,各个季节受盐分离子的影响较小,分布较为均匀。SAR介于3.08—5.29之间,春季受控于HCO~-_3;夏季受控于K~+;秋季受各离子的影响均较小,分布较为均匀。EC介于7.16—13.04 mS/cm,春季受各离子的影响均较小,其空间分布较为均匀;夏季受控于SO■、Ca~(2+)、Mg~(2+);秋季受控于Na~+。TS与Cl~-、Na~+、Mg~(2+)在季节变化上的差异性一致,且各个季节均受控于Cl~-。故通过合理的措施控制或减少Cl~-来源是一条减轻黄河口湿地土壤盐渍化的合适途径。

Characteristics of soil salinization in coastal wetlands based on canonical correspondence analysis

To develop and utilize wetland soil resources and ecological environment construction in the Yellow River Delta, a one-way variance analysis (ANOVA) and canonical correspondence analysis (CCA) were applied to analyse the seasonal distribution characteristics and quantitative relationships of total salt content (TS), ion composition, pH value, sodium adsorption ratio (SAR), and electrical conductivity (EC) in the surface layer (0-10 cm) of the soil profile. The results indicated that:(1) the soil of the study area belonged to the type of heavy solonchak,the mean soil salinity was more than 17.9 g/kg in spring (May), summer (August), and autumn (October) and the salt content in May and October was higher than that in August, which caused salification in spring and autumn and desalination in summer. (2)The dominate cation and anion of the soil were Na⁺ and Cl^-, respectively, Mg²⁺ expressed strong variability in summer and autumn and Cl^- in autumn, the other ions showed moderate intensity variation in different seasons. (3) Correlationships between Cl^- and Na⁺, Cl^- and Mg²⁺, and SO₄^2- and K⁺ were significant in May and Cl^- and HCO₃^-, SO₄^2- and Mg²⁺, SO₄^2- and Ca²⁺, Ca²⁺ and Mg²⁺ in August, and Cl^- and SO₄^2-, SO₄^2- and Mg²⁺, and Ca²⁺ and Mg²⁺ in October. (4) pH values varied between 7.7 and 8.1 and were less influenced by ions and more uniformly distributed in all three seasons. SAR varied between 3.08 and 5.29 and it was strongly influenced in May and K⁺ in August. It was weakly influenced by any ion and was distributed evenly in October. EC varied between 7.16 and 13.04 mS/cm and it was weakly influenced by ions in the soil and was distributed uniformly in May. However, it was significantly influenced by SO₄^2-, Ca²⁺, and Mg²⁺ in August, and Na⁺ in October. The seasonal variation in TS was coincident with Cl^-, Na⁺, and Mg²⁺, and Cl^- was the major factor controlling spatial distribution of soil total salt throughout all of three seasons. Therefore, controlling or reducing the Cl^- source is an optional approach to alleviate soil salinization in the wetlands of the Yellow River Delta.